Method of determining a shading and ventilation position for a roller band

ABSTRACT

A method and apparatus for determining a shading and ventilation position of a a roller blind. The method including steps of identifying the final slat position in which the bottom slat is at the limit of contact with the bottom end stop of the blind, assigning to this final slat position a data defining the position, and calculating a shading and ventilation position data defining the shading and ventilation position from the data of the final slat position. The method also includes steps of storing the shading and ventilation position data in a shading and ventilation position memory. The method enabling storing of the best shading and ventilation position without necessitating the storage in memory at the site of manufacture.

FIELD OF THE INVENTION

The invention relates to a method of determining a shading andventilation venting position in a control system of an actuator which isused to move a sun-protection, privacy or closure device. It alsoconcerns a device for controlling an actuator for moving asun-protection, privacy or closure device control device.

BACKGROUND OF THE INVENTION

It is known practice with control devices for roller blinds to determinean intermediate position of the roller blind, termed the shading andventilation position, which can be stored in memory by the installer orby the user.

In the case of a roller blind with perforated slats, the shading andventilation position is such that the shutter curtain of the blind isalmost fully unwound, the slats remaining separated from each other. Inthis separated position of the slats, elongate holes can be seen in thetop of each slat. These are normally hidden when the slats are restingon top of each other, as shown in FIG. 1. Such a situation provides theroom with privacy from the exterior and provides attenuated lighting,while allowing ventilation if the windows are not shut.

This position typically corresponds to 80–90% of the movement of thewinding drum of the blind required to close the blind. However, thisposition depends very much on the type of roller blind slats used in theconstruction of the shutter curtain.

EP 0 426 577 discloses just such a means of storing in memory anintermediate position and executing an instruction designed to move adevice to such a position. In that patent, a sensor is used to identifythe position of the winding tube driven by the actuator. In all cases itis up to the installer or user to store the intermediate position inmemory for the first time. This is done with the aid of a switchingdevice comprising control keys.

Patent EP 0 574 637 discloses ways of recording and executing a commandto enable an intermediate position to be reached in the case of anactuator without a position sensor. Here it is the duration of theoperation which is analyzed. An intermediate position is thereforeexpressed as a percentage of the total travel between the two extremepositions.

The disclosed devices have a drawback in that the intermediate orcomfortable position must necessarily be set either by the installer orby the user. Furthermore, if this setting is not carried out, the usermay remain unaware of the existence of this shading and ventilationposition function.

In Application FR 02 03668, it was suggested that devices be producedcomprising an intermediate position predefined by the manufacturer. Inthe case of a maker of roller blinds who knows the type of slat of eachdevice, it is possible to determine this intermediate positioninformation, for example as a percentage of the total travel. The mainadvantage of this prestored and predefined value is that it enables theinstaller to present the function to the customer and leave its preciseadjustment to the customer, at the customer's convenience. It is nottherefore necessary for the intermediate position to correspond to thebest shading and ventilation position.

This device has a drawback—it complicates production, since the type ofslat used in the roller blind must first be determined, and then thisintermediate-position data must be stored in memory.

SUMMARY OF THE INVENTION

The object of the invention is to provide a method of determining ashading and ventilation position that improves on the known methods ofthe prior art and mitigates the abovementioned drawbacks. In particular,the invention provides a method of automatically determining the bestshading and ventilation position without storing it in memory at thesite of the manufacturer.

The method according to the invention comprises the following steps:

-   -   identifying, by analyzing the torque exerted on the actuator,        the final slat position in which the bottom slat is at the limit        of contact with the bottom end stop of the device,    -   assigning to this final slat position a data defining said        position,    -   calculating a shading and ventilation position data defining the        shading and ventilation position from the data of the final slat        position, and    -   storing the shading and ventilation position data in a shading        and ventilation-position memory.

In this method, the addition of a value must be understood as adding arelative value which may correspond to subtracting a positive value.

The control device is characterized in that it comprises means forcalculating a data defining a position in which all the perforated partsare visible.

BRIEF DESCRIPTION OF THE DRAWINGS

The attached drawing shows by way of example one embodiment of themethod according to the invention.

FIG. 1 is a diagram showing a sequence of lifting a roller blind fromits closed position.

FIG. 2 is a diagrammatic view in cross section of the winding drum of aroller blind and of the different mechanical forces applied to it.

FIGS. 3 and 4 are diagrams showing the torque resisting the driving ofthe blind as a function of the angular position of the winding drum oras a function of time.

FIG. 5 is a diagram of a control device for carrying out the methodaccording to the invention.

FIG. 6 is a flowchart illustrating the method according to theinvention.

FIG. 7 is a flow chart for determining the shading and ventilationposition.

FIG. 8 is a flow chart illustrating the operation of a key for puttingthe blind in the shading and ventilation position.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The roller blind 1 shown in FIG. 1 is made up of several slats 2, 3connected to each other. The sequence of lifting this roller blind 1 isshown from left to right, beginning with its closed position. In thisfirst position the slats 2, 3 rest on top of each other. The torqueexerted by the blind on its winding drum (not shown) is therefore zero.

In the next three views, the lower slats are pulled up by the higherslats. This uncovers elongate holes in the slat parts 4 designed toconnect the slats together. Last of all, in the right-hand view, thebottom slat 3 has left its bottom position, so that the elongate holesare uncovered between all the slats 2, 3.

In this position, the weight of the roller blind suspended from thewinding drum is at maximum. However, the torque exerted on the drum isnot necessarily at maximum because the torque exerted on the windingdrum also depends on the winding radius.

As shown in a simplified manner in FIG. 2, the mass suspended increases,causing an increasing effort to be applied to the small radius, that isfirst F1, then F2. Given a constant angular velocity of the windingdrum, the torque increases in an approximately linear and rapid fashion.This is because a slat has only to rise by the height of one perforationbefore it is put in the next slat, which means the suspended mass isincreased.

When the suspended mass corresponds to a weight F3, it is assumed thatthe drum has wound through one complete revolution, at which pointwinding begins to occur at the second diameter. Because of this changeto a new winding diameter, the variation of torque that occurs when aslat first begins to rise is greater.

As soon as the bottom slat begins to rise, the suspended mass reaches amaximum. F4 denotes the new value of the weight of the suspended shuttercurtain. This weight then decreases as winding continues, passingthrough F5, then F6 and F7 on a larger diameter.

It will be noticed that, until the last slat has begun to rise, theaverage rate of decrease of the suspended mass (due to the winding ofthe slats around the drum) is generally less than the average rate ofincrease of the suspended mass (due to the lifting of new lower slats).This is due to the fact that one complete slat has to be wound for thesuspended mass to be reduced by one unit, whereas only a distancecorresponding to one perforation (that is, only about a third as far)has to be wound to increase it by one unit.

The curve, FIG. 3, is a typical example of a reading of torque againstthe angular position of the winding drum, in the case in which thebottom slat is not weighted. Such a curve can be obtained with the aidof a torque sensor and an angular-position sensor. An experimentalreading contains much more noise, but the use of a numerical filteringalgorithm removes the torque fluctuations.

In the case shown in FIG. 3, the blind takes 8 revolutions to wind up.The bottom slat here begins to rise at the end of the second revolutionP2. In the generally decreasing part of the torque, each new revolutionis clearly identifiable by a distinct torque increase (P3 to P7) in theopposite direction to the general decrease. In the increasing part,corresponding to the progressive opening up of the slats, the distincttorque increase corresponding to the beginning of the second revolutionP1 is harder to pinpoint. It can be seen however that, from thefrequency measured between the positions P3 to P7, the positions P1 andP2 can easily be identified by extrapolation if they are not very wellmarked.

The situation is a little more complicated if, as is often the case, thebottom slat is weighted. The torque maximum does not necessarilycorrespond to the moment when the bottom slat first begins to rise, butmay occur a little later, at the moment when the winding diameterincreases. This is illustrated in FIG. 4, which now corresponds to asimulation of the torque exerted by the blind on the drum as a functionof the lengths of shutter curtain wound up. The intermediate maximum,identified by an arrow, can be made out very easily. This is the torquevariation due to the bottom slat, which is weighted, beginning to rise.There is therefore no ambiguity about identifying the bottom slat,provided it is weighted.

The shading and ventilation position PIA is derived from the final slatposition PLF in which the bottom slat is at the limit of contact with abottom end stop. This shading and ventilation position corresponds tothe drum being wound up slightly less than for the PLF position.

A data dPIA defining the position PIA can therefore be deduced from adata dPLF defining the position PLF by the equationdPIA=dPLF−20,if the data are winding angles of the drum in degrees and if theposition PIA is 20° before the position PLF.

The data defining the two positions can also be related by a coefficientof proportionality, for example:dPIA=0.95×dPLF.

If the torque detection is very sensitive, or if no margin is taken, itis possible to simplify thus:dPIA=dPLF.

The control device 19 shown in FIG. 5 which can be used to carry out themethod according to the invention comprises a control unit 18 comprisinga microprocessor 10 able of running programs contained in a memory 12.The control unit 18 controls an actuator 11 that drives the roller blind1. Known to those skilled in the art, the details of the electricalconnections and power relays is not shown. The arrow 15 indicates thecontrol unit 18 has the option of acting on the actuator 11, while thearrow 16 indicates return information such as information from a torquesensor 22 to the actuator and, optionally, from an angular-positionsensor for the winding tube. The torque sensor used to measure thetorque is preferably situated in the actuator 11, but can also besituated somewhere else in the drive chain between the actuator and theblind. A memory area 13 is assigned to the storage of the shading andventilation position data dPIA and a memory area 14 is assigned to thestorage of an initialization algorithm comprising a program foracquiring torque and position readings and a program for calculating theshading and ventilation position data dPIA.

The control device 19 is supplied from an electricity supply 20 througha converter 21. A command transmitter 30 comprises control meansrepresented here by three keys 31, 32 and 33. The key 31 activates acontact giving the command to move to the shading and ventilationposition. The key 32 activates a contact giving a command to rise andthe key 33 activates a contact giving a command to descend.

As is known in the prior art, pressing a combination of these keys orpressing one for a long time causes the command transmitter to enter alearning mode. The command transmitter is connected to the control unitby a wire link 40 or by a wireless link (infrared, radio etc) as knownin the prior art. This link may be two-way, the command transmittercomprising lights or a display for acknowledging reception oftransmitted commands. The command transmitter may be separate from theactuator or integrated into a single mechanical assembly.

Pressing the key 31 activates the actuator 11 until the blind reachesthe shading and ventilation position which is calculated by aninitialization algorithm stored in memory 14.

One advantage of the invention is that it allows an instantaneousdemonstration of the function of setting the blind in the shading andventilation position, even if the setting is not exactly that desired bythe user. Having understood the effect of pressing the shading andventilation position key, the user will therefore be inclined to usethis function after first setting it to his convenience.

As shown in FIG. 6, following an action A1 by the installer, orderingthe system to enter the learning mode, the blind starts, in an initialphase 101, a first movement, e.g. of descent, until it meets a bottomend stop. This end stop is detected by the torque measuring device,which stops the activator and stores in memory a first end-of-travelposition FC1 or resets a timer to zero if the device does not have anangular-position sensor.

Immediately afterwards, the inner phase 102 of the actuator 11 drivesthe blind in the opposite direction. The torque sensor collects thetorque values CM exerted on the drum, and therefore on the actuator 11,as a function of winding position or of time. This recording phaselasts, for example, until a phase 103 in which the blind is detected tohave stopped on an end stop. The signal produced by the torque sensor isfiltered by a low-pass filter whose cut-off frequency is preferablyequal to or greater than the frequency of rotation of the winding drumso as to avoid producing a torque curve with numerous local extrema. Inthis phase, a second end-of-travel position FC2 is also recorded.

In the next phase 104, the data dPLF and dPIA used to define thepositions PLF and PIA are calculated, as explained later.

In phase 105, the shading and ventilation position is stored in thememory 13. At the end of this phase the control device comes out oflearning mode.

Following an action A2 by the user on the key 31 of the commandtransmitter 30, the control unit 18 receives the instructions to movethe blind to the shading and ventilation position. In phase 106, in thecontrol unit 18 determines the direction of movement and activates theactuator 11 until the blind is in the position PIA.

If the length of time the actuator has been running is used to determinethe position of the blind, the positioning of the blind in the positionPIA may necessitate first moving it through an end stop FC1 or FC2 inorder to reset the time to zero.

This method can also be used where the roller blind or any otherclosure, privacy or sun-protection device does not have a top end stop.The end-of-travel positions FC1 and/or FC2 can be determined by theinstaller by means of the transmitter and also by programming meansknown in the prior art. To simplify the data processing, it ispreferable for the movement between the positions FC1 and FC2 to beuninterrupted, but as described later, it is not indispensable for theinvention that the movement should take place from one end-of-travelstop to the other, provided that the variations of torque in thevicinity of the position where the bottom slat is at the limit ofcontact with the bottom end stop are recorded, at least on either sideof this position.

The flow chart, for FIG. 7, illustrates the method of determining thepositions PLF and PIA as used in phase 104 of the method describedabove.

In an initial sub-phase 201, all the local maxima CM(i) of the torque CMexerted on the drum during phase 102 and the corresponding positionsθ(i) of the blind are retrieved from memory.

The maxima are compared in order to determine which is the highest ofthem CM(k) and its position θ(k).

Clearly, it is not essential to know the position of all the maxima, butit will be observed that these data make it possible to deduce thewinding frequency, whether substantially constant or varying with theload in a known manner, and use this data if necessary to distinguishbetween a maximum due to the change of winding diameter, and a maximumdue to the rising of the weighted bottom slat should these two be veryclose together.

In the case of well defined maxima, a simple discrimination issufficient. This can be done via a test 202 that determines whetherthere is a local maximum whose position is closer to the closed positionof the blind than is the position of the global maximum. The index (k−1)is assigned to the position of a local maximum situated between theclosed position of the blind and the position of the global maximumtorque.

If the result of this test is negative, the position PLF in which thebottom slat is at the limit of contact with the bottom end stop isdefined, in sub-phase 203, as the position θ(k) of the global maximumtorque.

If the result of the test is positive, the position PLF in which thebottom slat is at the limit of contact with the bottom end stop isdefined in sub-phase 204 as the position θ(k−1) of the local maximumexisting between the closed position of the blind and the position θ(k)of the global maximum torque.

Lastly, in sub-phase 205, the shading and ventilation position PIA isdefined from the position PLF in which the bottom slat is at the limitof contact with the bottom end stop. This definition may consist insubtracting a number or applying a multiplying coefficient to the datadPLF defining the position PLF. The data defined in the positions PIAand PLF may be drum winding angles, the lengths of time for which theactuator 11 has been running from a reference position, or images ofthese variables.

Finally, as in the prior art, the user or installer still has the optionof recording a position data defining a customized position which theusers prefers. It is preferably recorded directly by overwriting thecalculated value PIA in the memory 13.

The invention is carried out more easily by using a command transmitterthat comprises a reduced number of keys and that facilitates theunderstanding of the functions. To this end, the invention proposes thatthe above device be implemented with a command transmitter having akeypad with three keys. The key 31 gives a command to move to theshading and ventilation position, when the actuator 11 is not running,and to stop when the actuator 11 is running.

As shown in FIG. 8, the first step 301 tests the status of the key 31.If this key is actuated, the second step 302 tests to see whether theactuator is running:

-   -   if it is running, proceed to a step 304 in which the actuator 11        is turned off,    -   if it is not running, proceed to a step 303 in which the command        transmitter sends a command telling the shutter to move to the        shading and ventilation position PIA.

Consequently, the invention doubly facilitates the use of the functiongiving access to a shading and ventilation position, firstly by means ofa method which makes this function usable in an almost optimal function,without on-site adjustment, and secondly by the use ofcommand-transmitting means that assist a clear understanding of thefunctions by the use of a limited number of keys.

1. A method of determining a shading and ventilation venting position(PIA) in a control system of an actuator (11) which is used to move asun-protection, privacy or closure device (1) comprising stackable slats(2, 3) connected together by perforated parts (4), which methodcomprises the following steps: identifying, by analyzing the torqueexerted on the actuator (11), the final slat position (PLF) in which thebottom slat (3) is at the limit of contact with the bottom end stop ofthe device (1), assigning to this final slat position (PLF) a data(dPLF) defining said position, calculating a shading and ventilationposition data (dPIA) defining the shading and ventilation position (PIA)from the data (dPLF) of the final slat position (PLF), and storing theshading and ventilation position data (dPIA) in a shading andventilation position memory (13).
 2. The method as claimed in claim 1,wherein the step of “identifying, by analyzing the torque exerted on theactuator (11), the final slat position (PLF) in which the bottom slat(3) is at the limit of contact with the bottom end stop of the device(1)” comprises the following sub-steps: by means of the actuator (11),driving the device (1) at least to the vicinity of the final slatposition (PLF), such that it passes through the final slat position(PLF), storing, during the preceding sub-step, the values of the torqueexerted on the actuator (11) by the weight of the device (1), based onthe position of the device (1), and determining the final slat position(PLF) as corresponding to the first local torque maximum encounteredafter leaving the completely unwound position of the device (1).
 3. Amethod for controlling an actuator (11) making it possible to move asun-protection, privacy or closing device (1) to a shading andventilation position (PIA), which method includes the steps of themethod as claimed in claim 1, and the following steps: activating theactuator (11) at the time of the transmission of a shading andventilation position control command, until the device (1) occupies theposition defined by the shading and ventilation position data (dPIA)stored in the shading and ventilation position memory (13).
 4. Themethod as claimed in claim 1, wherein the data defining the shading andventilation position (PIA) is derived from a data defining the finalslat position (PLF) by multiplying it by a coefficient.
 5. The method asclaimed in claim 1, wherein the data defining the shading andventilation position (PIA) is derived from a data defining the finalslat position (PLF) with a mathematical law comprising an addition.
 6. Adevice (19) for controlling an actuator (11) for moving asun-protection, privacy or closure device (1) comprising stackable slats(2, 3) connected together by perforated parts (4) and comprising atorque sensor (22), which device comprises means (10) for calculating adata (dPIA) defining a position (PIA) in which all the perforated parts(4) are visible.
 7. The device as claimed in claim 6, which devicecomprises a command transmitter (30) having a shading and ventilationposition key (31) activating a contact that causes the actuator (11) tomove the sun-protection, privacy or closure device (1) to the shadingand ventilation position (PIA) if the actuator (11) is not activated andthat causes the actuator (11) to stop if it is activated.